In the 1960's in Scotland a man killed three women. All of them came from the Barrowland Ballroom, they were all mothers, and all menstruating. They were beaten, then strangled. The last victim had a bite mark on her arm. While this suggested a pattern of escalation. Instead the killing stopped. The man disappeared and the cases have remained unsolved.
Sources:
MacGregor, Steve. 2018. Murder World Scotland. The Face of Bible John. The hunt for a Scottish serial killer
https://www.bbc.com/news/uk-scotland-glasgow-west-63916850
